-e filename 如果 filename存在，则为真
-d filename 如果 filename为目录，则为真
-f filename 如果 filename为常规文件，则为真
-L filename 如果 filename为符号链接，则为真
-r filename 如果 filename可读，则为真
-w filename 如果 filename可写，则为真
-x filename 如果 filename可执行，则为真
-s filename 如果文件长度不为0，则为真
-h filename 如果文件是软链接，则为真
如果存在某文件，则删除
if [ -f trials ]; then rm ${result_path}trials; fi如果没有文件夹，则创建
if [ ! -d $result_name ];then
mkdir -p $result_name
fi
shell命令判断文件或文件夹是否存在，先直接看实例：
#!/bin/sh
#判断文件存在，判断是否为文件夹等
testPath="/Volumes/MacBookProHD/Mr.Wen/08 shell命令"
testFile="/Volumes/MacBookProHD/Mr.Wen/08 shell命令/fileWen"
#判断文件夹是否存在 -d
if [[ ! -d "$testPath" ]]; then
echo "文件夹不存在"
else
echo "文件夹存在"
fi
#判断文件夹是否存在，并且具有可执行权限
if [[ ! -x "$testFile" ]]; then
echo "文件不存在并且没有可执行权限"
else
echo "文件存在并有可执行权限"
fi
#判断文件是否存在
if [[ ! -f "$testFile" ]]; then
echo "文件不存在"
else
echo "文件存在"
fi
在shell命令脚本编写当中，会遇到各种对文件的判断，除了以上常用的判断，还有其他的可以使用，如下：
Conditional Logic on Files -a file exists. -b file exists and is a block special file. -c file exists and is a character special file. -d file exists and is a directory. -e file exists (just the same as -a). -f file exists and is a regular file. -g file exists and has its setgid(2) bit set. -G file exists and has the same group ID as this process. -k file exists and has its sticky bit set. -L file exists and is a symbolic link. -n string length is not zero. -o Named option is set on. -O file exists and is owned by the user ID of this process. -p file exists and is a first in, first out (FIFO) special file or named pipe. -r file exists and is readable by the current process. -s file exists and has a size greater than zero. -S file exists and is a socket. -t file descriptor number fildes is open and associated with a terminal device. -u file exists and has its setuid(2) bit set. -w file exists and is writable by the current process. -x file exists and is executable by the current process. -z string length is zero.
shell 判断文件内容是否改变
判断文件内容是否改变：
1）md5值判断
2）diff 判断
#添加日志时间戳
function fn_showlog()
{
local curtime;
curtime=`date +"%Y%m%d-%H:%M:%S"`
echo "$curtime ------ $1";
}
#判断文件内容是否一致
function diff_file(){
for file in `ls $1`
do
if [ ! -f "$2$file" ];then
fn_showlog "存在新增文件：$2$file"
return 0
else
diff $file $2$file
if [ $? -ne 0 ];then
fn_showlog "文件内容发生变化：$file"
return 0
fi
fi
done
return 1
}
diff_file "python*Ip" "/home/admin/tools/"
if [ $? -eq 0 ];then
fn_showlog "内容发生改变......"
else
fn_showlog "内容未发生改变，退出脚本!"
exit 0
fi